Cycle News - Archive Issues - 1980's

~ 00 ,......; perform just as well as the allelectronic mixers on the 1100. Therewa n'tmuchopportunityto simulate city riding at Laguna Seca, but d liberate allempts to fool the carburetion had no effect. It didn't maller what combination of throllie position. engine speed and load were applied, the 900R always carbureted just as smoothly a the fuel-injected 1I00s on hand for comparison. The new 900 was also smoother and quieter than any other bi ke at the track. The GPz II 00 sounded positively rallley compared to the muffled hum that managed to pass through the 900's liquid-cooling jacket. Smoothness was a particular problem for Kawasaki designers when, in the interests of savi ng weigh t, they decided to use the new motor as a stressed member of the GPz's frame. Rubber motor mounts ould not be used if the powerplant was to double duty as frame front downtube and engine cradle. With thecvlinder head bolted directly to the frame Just below the steering head and the gearbox bolted to the swingarm pivot area, a counterbalancer wa the only way to reduce the effects of engine vibration. The 900R is the first in-line-four motorcycle engine to use a single counler-balan er. It's gear driven directly 0[£ the crank and spins in the motor's wet sump. To further reduce frame weight Kawasaki uses large aluminum castings bolted to the frame backbone to provide outboard support for the aluminum swingarm. The remaining rear seetin of the frame, supporting the seat and rear fender, is a lightweight"square-section unit that bolts up to the main frame. The entire structure does not appear to offer much rigidi ty but one fast lap of Laguna Seca proved that Kawasaki has produced a chassis that others will probably be judged by. The GPz900R can be t be described as having the taut feel of a road racer, an attribute rarely present in road-goin~ motorcycles. As a result, the new Kawasaki can be pushed hard over bumps and ripples without a weave or wobble. The same could not be said for the GPzIIOO and 750 Turbo under the same conditions. This firm feel can also be attributed to refinements in Kawasaki's Uni-Trak rear suspension and antidive front forks. The rear suspension has the same linkage below the swingarm as the other GPz models, connected LO a single spring-and-air shock. Air pressure can be altered through a remote valve just above the swingarm pivot while a small knob alters the four rebound damping settings. Even more elaborate is Kawasaki's new AVOS front fork. The Automatic Variable Damping System increases compression damping relative LO theamount of travel and speed at which the fork compresses. After almost twO inches of fork travel the' main fork spring pushes against the AVOS valve sufficiently to restrict the flow of damping fluid. Thedamping rate cOlllinues to increase until late in the suspension travel when a econd valve blows of( to prevent a hydraulic lock in the system. Just sitting on the bike and compressing the suspension gives no indication of how well the system works. Both end of the 900R feel as plu has any suspension on the market. In fact, that's how it continues to feel as you roll along at around-town speeds. But the second you gain some speed and really start using the suspension the Kawasaki sudden Iy seems to stiffen up. Combined with the excellent chassis, this firm feel is ideal for gofast riding. There is none of the bobbling and wobbling that many bikes exhibit when pushed to the limit and yet the ride never becomes uncomfortably harsh. The AVOS fork does a prelly good job under heavy braking LOO. A big handful offront brake won't collapse the front end although the Kawasaki system till doesn't reduce dive as much as Honda's excellent TRAC mechani m. Then again. the 900R does have as much brake as you'll find on any street bike. The drilled double front discs have good feel and enough power to slow the bike even from racing speeds. Only after continuous stops from Laguna Seca's faster sections did the pads start to overheat. but that is far more abuse than even the [as test street ride could produce. Dunlop's new l6-inch FI7 frolll tire and 18-inch K727 rear are also more than up to thejobofhigh-speed riding. They complemented the Kawasaki's racer-like feel perfectly and, to everyone 's surprise. they showed minimal wear after twO days of race track testi ng. About the only thing that the race track couldn't uncover was the streetriding practicality of the GPz's riding position. The comfortable new seat is just over an inch lower than the old GPzIIOO' so you feel to sit in the motorcycle more than other GPt's. The wide, sculptured gas tank is also taller than previous GPz tanks so there is a feeling of draping across the recessed filler cap LO grab the cast aluminum bars. At speed the ridin~ position felt very good, but many Americans will probably want less of a European crouch while they cruise the superslab. But whatever the 900R lacks in a ride-to-work riding po ition it more than makes up for in what Americans love best: Horsepower. It· a red rocket in true Kawasaki tradition. And if you're wondering how fast a downsized superbike can be, how doe a 10.559-second quarter mile at 132 mph sound? That's what the bike is capable of in the professional hands of Pee Wee Gleason and that leaves plenty of room for even average riders to dip inLO the magical lOs. And don't forget that the GPz900R is almost as fast around turn as it is at the strip and that's what raises the bike above many so-called superbikes. II's truly super in every area and unlike the Turbos that were heralded with similar claims. Kawasaki's GPz900R really does combine the power of an 1100 with the agility of a 750. That's what makes the GP,900R a real superbike. • Specifications Engine Type Displacement Bore x stroke Compression ratio Starting system Ignition system Transmission Carburetor Liquid-cooled four-cylinder DOHC four-stroke. 908cc. 72.5 X 55.0mm. 11.0: 1 . Electric. C.D.1. Six-speed. Keihin CVK34. Frame Type Tubular diamond. Front tire 120/80 V16 Dunlop. Rear tire .......................•.......... . 130/80 V18 Dunlop. Dimensions Wheelbase Seat height Dry weight (claimed) Fuel capacity Oil capacity Suggested retail price 58.9 in. 30.7 in. 502.6 Ibs. 5.8 gal. 4.0 Itrs. TBA

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